Haptics is a technique related to touch and specifically refers to a technique that allows a user of an electronic device to feel a touch, a force, and a sense of movement through a keyboard, a mouse, a joystick, and a touch screen. In the past, visual and auditory means have been mainly used as means of exchanging information between users and electronic devices, but recently, haptic technology has been attracting attention for more specific and realistic information transmission.
In general, a haptic providing device based on the haptic technology may include an inertial actuator, a piezoelectric actuator, an electro-active polymer actuator (EAP), and an electrostatic actuator.
The inertial actuator may include an eccentric rotation motor (ERM) that vibrates using an eccentric force generated by a body of weight connected to a magnetic circuit and a linear resonant actuator (LRA) that maximizes an intensity of vibration using a resonance frequency generated by the body of weight connected to the magnetic circuit and an elastic spring.
In terms of a linear resonance actuator in the haptic providing device of the related art, there are Korean Patent Registration No. 10-1461274 (entitled: LINEAR MOTOR) and Korean Patent Laid-open Publication No. 10-2016-0021160 (entitled: SPRING AND LINEAR VIBRATION MOTOR THEREWITH).
The piezoelectric actuator may be a device that is driven in a form of a bar or a disk based on a piezoelectric element of which an external shape changes instantaneously by an electric field. In the related art, there are Korean Patent Registration No. 10-1603957 (entitled: PIEZOELECTRIC ACTUATOR, PIEZOELECTRIC VIBRATION APPARATUS AND PORTABLE TERMINAL) and Korean Patent Laid-open Publication No. 10-2011-0118584 (entitled: TRANSPARENT COMPOSITE PIEZOELECTRIC COMBINED TOUCH SENSOR AND HAPTIC ACTUATOR).
The EPA may be a device that is driven based on repetitive movements provided by attaching an electro-active polymer film to a mass. The EPA may be based on a principle that a shape of the electro-active polymer film is changed by a functional group of a polymer backbone having a specific mechanism by external electric power. In the related art, there is U.S. Patent Application Publication No. US2016/0049576 (entitled: ACTUATOR STRUCTURE AND METHOD).
In addition to the above-mentioned haptic providing device, haptic providing device using a shape memory apply, an electrostatic force, an ultrasonic wave, and the like have been developed.
However, the above-mentioned haptic providing device merely transmits a simple vibration and thus, there is a limit to transmission of emotional tactile feedbacks or complex character information.
Korean Patent Registration No. 10-1556970 (entitled: SIMULATION OF THREE DIMENSIONAL MOTION USING HAPTIC ACTUATORS) discloses a method and apparatus for simulating a three-dimensional (3D) motion using haptic actuators, which, however, is to simulate a motion of a dynamic object by “sequentially” activating or deactivating a plurality of haptic actuators in a user device based on a predetermined reference instead of implementing 3D vibration or “tactile sense” such as a sense of rubbing using a single actuator.
Accordingly, there is a desire for research on a tactile sense transmitting structure for effectively transmitting more sensitive and complex emotion and information in addition to a simple vertical vibration in order to transmit a variety of information through a tactile sense besides visual and auditory senses.